Rapid advances in electronics and communications technologies, driven by immense customer demand, have resulted in the widespread adoption of data-driven devices, including cellular phones, smart phones and global positioning devices (GPSs), to name just a few. Envelope detectors (EDs) detect the voltage amplitude of a radio frequency (RF) signal output from a transmitter (TX) of such cellular devices for purposes of calibration or power detection. For instance, the envelope or peak information of the TX output may be used for calibration of LOFT (Local Oscillator (LO) feedthrough), IQ (in-phase/quadrature) mismatch and power level control. An envelope detector can also be used for envelope tracking of voltage amplifier supply to save power by decreasing the supply when the output is low. Peak to average ratio and dynamic range of the TX output may require stringent linear ranges for an ED core integrated within a cellular transmitter. During ED conversion, a linearity accuracy within plus or minus 0.5 dB may be expected for proper calibration and envelope tracking.